How to Scan on Yosemite 10.10.3
Printer / Scanner: Lexmark S605 (other scanners should work also)
1. Do NOT update ANY drivers, etc., from printer manufacturer.
2. Open your Mac Computer System Preferences (under the Apple symbol, top left).
3. Open "Printers & Scanners"
4. Your Lexmark (or other) should be listed?
5. Select your printer.
6. On right side of Printers & Scanners window it should have two oblong buttons "PRINT" "SCAN"
7. Select Scan.
8. A New window should open and automatically do a rescan of your document on your scanner.
9. Adjust the Scanner options, i.e., Resolution, Scan to, Name new document, Format, etc.
10. Click Scan and it should scan your document to your selected location.
Hope this helps. It's a pain in the rear having to scan from the System Preferences, but it was the only way I could figure it out.
Paul
iMac 27"